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Quan PQ, Guo PL, He J, Liu XD. Heat-stress memory enhances the acclimation of a migratory insect pest to global warming. Mol Ecol 2024:e17493. [PMID: 39132714 DOI: 10.1111/mec.17493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 07/18/2024] [Accepted: 08/02/2024] [Indexed: 08/13/2024]
Abstract
In the face of rising global temperatures, the mechanisms behind an organism's ability to acclimate to heat stress remain enigmatic. The rice leaf folder, Cnaphalocrocis medinalis, traditionally viewed as temperature-sensitive, paradoxically exhibits robust larval acclimation to heat stress. This study used the heat-acclimated strain HA39, developed through multigenerational exposure to 39°C during the larval stage, and the unacclimated strain HA27 reared at 27°C to unravel the transgenerational effects of heat acclimation and its regulatory mechanisms. Heat acclimation for larvae incurred a fitness cost in pupae when exposed to high temperature, yet a significant transgenerational effect surfaced, revealing heightened fitness benefit in pupae from HA39, even without additional heat exposure during larval recovery at 27°C. This transgenerational effect exhibited a short-term memory, diminishing after two recovery generations. Moreover, the effect correlated with increased superoxide dismutase (SOD) enzyme activity and expression levels of oxidoreductase genes, representing physiological and molecular foundations of heat acclimation. Heat-acclimated larvae displayed elevated DNA methylation levels, while pupae from HA39, in recovery generations, exhibited decreased methylation indicated by the upregulation of a demethylase gene and downregulation of two methyltransferase genes at high temperatures. In summary, heat acclimation induces DNA methylation, orchestrating heat-stress memory and influencing the expression levels of oxidoreductase genes and SOD activity. Heat-stress memory enhances the acclimation of the migratory insect pest to global warming.
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Affiliation(s)
- Peng-Qi Quan
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Pan-Long Guo
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Jing He
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Xiang-Dong Liu
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
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2
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Bussy M, Destierdt W, Masnou P, Lazzari C, Goubault M, Pincebourde S. The lack of plasticity and interspecific variability in thermal limits produce a highly heat-tolerant tropical host-parasitoid system. J Therm Biol 2024; 123:103930. [PMID: 39116624 DOI: 10.1016/j.jtherbio.2024.103930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 07/19/2024] [Accepted: 07/21/2024] [Indexed: 08/10/2024]
Abstract
Thermal limits are often used as proxies to assess the vulnerability of ectotherms to environmental change. While meta-analyses point out a relatively low plasticity of heat limits and a large interspecific variability, only few studies have compared the heat tolerance of interacting species. The present study focuses on the thermal limits, and their plasticity (heat hardening), of three species co-occurring in Western Africa: two ectoparasitoid species, Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae) and Eupelmus vuilleti (Crawford) (Hymenoptera: Eupelmidae), and their common host, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). The investigation delves into the Critical Thermal Maximum (CTmax), representing the upper tolerance limit, to understand how these species may cope with extreme thermal events. The CTmax of all three species appeared similarly high, hovering around 46.5 °C, exceeding the global mean CTmax observed in insects by 3.5 °C. Short-term exposure to moderate heat stress showed no impact on CTmax, suggesting a potential lack of heat hardening in these species. Therefore, we emphasized the similarity of heat tolerance in these interacting species, potentially stemming from both evolutionary adaptations to high temperatures during development and the stable and similar microclimate experienced by the three species over the years. While the high thermal tolerance should allow these species to endure extreme temperature events, the apparent lack of plasticity raises concerns about their ability to adapt to future climate change scenarios. Overall, this research provides valuable insights into the thermal physiology of these interacting species, providing a basis for understanding their responses to climate change and potential implications for the host-parasitoid system.
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Affiliation(s)
- Mathieu Bussy
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS, University of Tours, Tours, France.
| | - Wendy Destierdt
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS, University of Tours, Tours, France
| | - Pauline Masnou
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS, University of Tours, Tours, France
| | - Claudio Lazzari
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS, University of Tours, Tours, France
| | - Marlène Goubault
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS, University of Tours, Tours, France
| | - Sylvain Pincebourde
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS, University of Tours, Tours, France
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3
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Lenard A, Diamond SE. Evidence of plasticity, but not evolutionary divergence, in the thermal limits of a highly successful urban butterfly. JOURNAL OF INSECT PHYSIOLOGY 2024; 155:104648. [PMID: 38754698 DOI: 10.1016/j.jinsphys.2024.104648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 05/11/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024]
Abstract
Despite the generally negative impact of urbanization on insect biodiversity, some insect species persist in urban habitats. Understanding the mechanisms underpinning the ability of insects to tolerate urban habitats is critical given the contribution of land-use change to the global insect decline. Compensatory mechanisms such as phenotypic plasticity and evolutionary change in thermal physiological traits could allow urban populations to persist under the altered thermal regimes of urban habitats. It is important to understand the contributions of plasticity and evolution to trait change along urbanization gradients as the two mechanisms operate under different constraints and timescales. Here, we examine the plastic and evolutionary responses of heat and cold tolerance (critical thermal maximum [CTmax] and critical thermal minimum [CTmin]) to warming among populations of the cabbage white butterfly, Pieris rapae, from urban and non-urban (rural) habitats using a two-temperature common garden experiment. Although we expected populations experiencing urban warming to exhibit greater CTmax and diminished CTmin through plastic and evolutionary mechanisms, our study revealed evidence only for plasticity in the expected direction of both thermal tolerance traits. We found no evidence of evolutionary divergence in either heat or cold tolerance, despite each trait showing evolutionary potential. Our results suggest that thermal tolerance plasticity contributes to urban persistence in this system. However, as the magnitude of the plastic response was low and comparable to other insect species, other compensatory mechanisms likely further underpin this species' success in urban habitats.
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Affiliation(s)
- Angie Lenard
- Department of Biology, Case Western Reserve University, 2074 Adelbert Rd, Cleveland, OH 44106, USA.
| | - Sarah E Diamond
- Department of Biology, Case Western Reserve University, 2074 Adelbert Rd, Cleveland, OH 44106, USA
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4
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Gunderson AR. Disentangling physiological and physical explanations for body size-dependent thermal tolerance. J Exp Biol 2024; 227:jeb245645. [PMID: 38426549 DOI: 10.1242/jeb.245645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
The effects of climate change are often body size dependent. One contributing factor could be size-dependent thermal tolerance (SDTT), the propensity for heat and cold tolerance to vary with body size among species and among individuals within species. SDTT is hypothesized to be caused by size differences in the temperature dependence of underlying physiological processes that operate at the cellular and organ/system level (physiological SDTT). However, temperature-dependent physiology need not change with body size for SDTT to be observed. SDTT can also arise because of physical differences that affect the relative body temperature dynamics of large and small organisms (physical SDTT). In this Commentary, I outline how physical SDTT occurs, its mechanistic differences from physiological SDTT, and how physical and physiological SDTT make different predictions about organismal responses to thermal variation. I then describe how physical SDTT can influence the outcome of thermal tolerance experiments, present an experimental framework for disentangling physical and physiological SDTT, and provide examples of tests for physiological SDTT that control for physical effects using data from Anolis lizards. Finally, I discuss how physical SDTT can affect organisms in natural environments and influence their vulnerability to anthropogenic warming. Differentiating between physiological and physical SDTT is important because it has implications for how we design and interpret thermal tolerance experiments and our fundamental understanding of thermal ecology and thermal adaptation.
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Affiliation(s)
- Alex R Gunderson
- Department of Ecology & Evolutionary Biology, Tulane University, 6823 St Charles Avenue, Lindy Boggs Building Room 400, New Orleans, LA 70118-5698, USA
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5
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Mlambo S, Mubayiwa M, Tarusikirwa VL, Machekano H, Mvumi BM, Nyamukondiwa C. The Fall Armyworm and Larger Grain Borer Pest Invasions in Africa: Drivers, Impacts and Implications for Food Systems. BIOLOGY 2024; 13:160. [PMID: 38534430 DOI: 10.3390/biology13030160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/09/2023] [Accepted: 11/13/2023] [Indexed: 03/28/2024]
Abstract
Invasive alien species (IAS) are a major biosecurity threat affecting globalisation and the international trade of agricultural products and natural ecosystems. In recent decades, for example, field crop and postharvest grain insect pests have independently accounted for a significant decline in food quantity and quality. Nevertheless, how their interaction and cumulative effects along the ever-evolving field production to postharvest continuum contribute towards food insecurity remain scant in the literature. To address this within the context of Africa, we focus on the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), and the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), two of the most important field and postharvest IAS, respectively, that have invaded Africa. Both insect pests have shown high invasion success, managing to establish themselves in >50% of the African continent within a decade post-introduction. The successive and summative nature of field and postharvest damage by invasive insect pests on the same crop along its value chain results in exacerbated food losses. This systematic review assesses the drivers, impacts and management of the fall armyworm and larger grain borer and their effects on food systems in Africa. Interrogating these issues is important in early warning systems, holistic management of IAS, maintenance of integral food systems in Africa and the development of effective management strategies.
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Affiliation(s)
- Shaw Mlambo
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Private Bag 16, Palapye 10071, Botswana
| | - Macdonald Mubayiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Private Bag 16, Palapye 10071, Botswana
| | - Vimbai L Tarusikirwa
- Department of Biology, The University of Western Ontario, London, ON N6A 5B7, Canada
| | - Honest Machekano
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
| | - Brighton M Mvumi
- Department of Agricultural and Biosystems Engineering, University of Zimbabwe, Mount Pleasant, Harare P.O. Box MP167, Zimbabwe
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Private Bag 16, Palapye 10071, Botswana
- Department of Zoology and Entomology, Rhodes University, Makhanda 6140, South Africa
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6
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Aragon-Traverso JH, Piñeiro M, Olivares JPS, Sanabria EA. Temporal variation of thermal sensitivity to global warming: Acclimatization in the guitarist beetle, Megelenophorus americanus (Coleoptera: Tenebrionidae) from the Monte Desert. Comp Biochem Physiol A Mol Integr Physiol 2023; 285:111505. [PMID: 37619666 DOI: 10.1016/j.cbpa.2023.111505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/28/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023]
Abstract
Global warming is a major threat to biodiversity, the increase in mean temperature plus the higher rate and intensity of heat waves can severely affect organisms by exposing them to temperatures beyond their tolerance limits. Desert ectotherms are particularly vulnerable due to their dependence on environmental temperatures in an extreme habitat. Thermal tolerance changes depending on environmental conditions, studying these fluctuations provides a better understanding of species susceptibility to global warming. Tenebrionids are successful desert-inhabiting ectotherm taxa because of a series of adaptations for heat tolerance and water loss. We studied the seasonal variation (acclimatization) of thermal tolerance in Megelenophorus americanus, a widely distributed species in the Monte Desert (Argentina). To do this, we measured environmental and operative temperatures: body temperature (Tb), soil temperature (Ts), air temperature (Ta), environmental temperature (Te) and maximum temperature (Tmax), and tolerance proxies volunteer thermal maximum (VTmax), Fluid release (FR) and critical thermal maximum (CTmax) in a population of M. americanus from San Juan province, Argentina from October to March (full activity season). We found that Ts and Ta are accurate predictors of Tb, suggesting thermoconformism. All tolerance proxies showed differences among months, suggesting a natural acclimatization process in situ. Insects were found operating beyond VTmax (thermal stress) but they were far from reaching CTmax under natural conditions. Organisms present different degrees of tolerance plasticity that should be considered when predicting potential impacts of climate change.
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Affiliation(s)
- Juan Hector Aragon-Traverso
- Instituto de Ciencias Básicas, Facultad de Filosofía Humanidades y Artes, Universidad Nacional de San Juan, Av. José Ignacio de la Roza 230 (O), San Juan 5400, Argentina; CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, CCT, San Juan, Argentina.
| | - Mauricio Piñeiro
- CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, CCT, San Juan, Argentina; Instituto de Biotecnología, Facultad de ingeniería, Universidad Nacional de San Juan, Avenida Libertador Gral. San Martín 1109 (O), San Juan 5400, Argentina
| | - Juan Pablo Segundo Olivares
- Departamento de Biología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan, Av. José Ignacio de la Rosa y Meglioli, 5400 San Juan, Argentina
| | - Eduardo Alfredo Sanabria
- Instituto de Ciencias Básicas, Facultad de Filosofía Humanidades y Artes, Universidad Nacional de San Juan, Av. José Ignacio de la Roza 230 (O), San Juan 5400, Argentina; CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, CCT, San Juan, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo. Padre Contreras 1300, Mendoza 5500, Argentina
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7
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Nacko S, Hall MA, Gloag R, Lynch KE, Spooner-Hart RN, Cook JM, Riegler M. Heat stress survival and thermal tolerance of Australian stingless bees. J Therm Biol 2023; 117:103671. [PMID: 37677867 DOI: 10.1016/j.jtherbio.2023.103671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 07/14/2023] [Accepted: 07/15/2023] [Indexed: 09/09/2023]
Abstract
Stingless bees (Meliponini) are important pollinators throughout the world's tropical and subtropical regions. Understanding their thermal tolerance is key to predicting their resilience to changing climates and increasingly frequent extreme heat events. We examined critical thermal maxima (CTmax), survival during 1-8 h heat periods, chill coma recovery and thermal preference for Australian meliponine species that occupy different climates across their ranges: Tetragonula carbonaria (tropical to temperate regions), T. hockingsi (tropical and subtropical regions only) and Austroplebeia australis (widely distributed including arid regions). We found interspecific differences in thermal tolerance consistent with differences in the climate variability observed in each species' range. Foragers of A. australis had a faster chill coma recovery (288 s) than foragers of T. hockingsi (1059 s) and T. carbonaria (872 s). Austroplebeia australis also had the highest CTmax of 44.5 °C, while the CTmax of the two Tetragonula species was ∼43.1 °C. After a 1-h heat exposure, T. carbonaria foragers experienced 95% mortality at 42 °C, and 100% at 45 °C. Surprisingly, larvae and pupae of both Tetragonula species were more resistant to heat exposure than foragers. Within an enclosed temperature gradient apparatus (17-38 °C), no clear preference was found for foragers; however, they were most frequently observed at ∼18 °C. Results indicate that in some regions of Australia, meliponines already experience periodic heat events exceeding their thermal maxima. Employing effective management strategies (such as nest site insulation and habitat preservation) may be crucial to colony survival under continued climate change.
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Affiliation(s)
- Scott Nacko
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
| | - Mark A Hall
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Rosalyn Gloag
- School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Kate E Lynch
- Department of Philosophy and Charles Perkins Centre, University of Sydney, Camperdown, NSW, 2006, Australia
| | - Robert N Spooner-Hart
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - James M Cook
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Markus Riegler
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
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8
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Mbande A, Mutamiswa R, Chidawanyika F. Ontogenetic responses of physiological fitness in Spodoptera frugiperda (Lepidoptera: Noctuidae) in response to repeated cold exposure. BULLETIN OF ENTOMOLOGICAL RESEARCH 2023; 113:449-455. [PMID: 37587795 DOI: 10.1017/s0007485323000111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
In this era of global climate change, intrinsic rapid and evolutionary responses of invasive agricultural pests to thermal variability are of concern given the potential implications on their biogeography and dire consequences on human food security. For insects, chill coma recovery time (CCRT) and critical thermal minima (CTmin), the point at which neuromuscular coordination is lost following cold exposure, remain good indices for cold tolerance. Using laboratory-reared Spodoptera frugiperda (Lepidoptera: Noctuidae), we explored cold tolerance repeated exposure across life stages of this invasive insect pest. Specifically, we measured their CTmin and CCRT across four consecutive assays, each 24 h apart. In addition, we assessed body water content (BWC) and body lipid content (BLC) of the life stages. Our results showed that CTmin improved with repeated exposure in 5th instar larvae, virgin males and females while CCRT improved in 4th, 5th and 6th instar larvae following repeated cold exposure. In addition, the results revealed evidence of cold hardening in this invasive insect pest. However, there was no correlation between cold tolerance and BWC as well as BLC. Our results show capacity for cold hardening and population persistence of S. frugiperda in cooler environments. This suggests potential of fall armyworm (FAW) to withstand considerable harsh winter environments typical of its recently invaded geographic range in sub-Saharan Africa.
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Affiliation(s)
- Abongile Mbande
- Department of Zoology and Entomology, University of the Free State, Bloemfontein, South Africa
| | - Reyard Mutamiswa
- Department of Zoology and Entomology, University of the Free State, Bloemfontein, South Africa
- Tugwi-Mukosi Multidisciplinary Research Institute, Midlands State University, Gweru, Zimbabwe
- Department of Zoology and Entomology, Rhodes University, Makhanda, South Africa
| | - Frank Chidawanyika
- Department of Zoology and Entomology, University of the Free State, Bloemfontein, South Africa
- International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya
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9
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Han G, Du Y, Du L. Effects of heating rate and shell colour on the cardiac thermal performance in a polymorphic gastropod Batillaria attramentaria. MARINE ENVIRONMENTAL RESEARCH 2023; 189:106045. [PMID: 37295309 DOI: 10.1016/j.marenvres.2023.106045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/31/2023] [Accepted: 06/03/2023] [Indexed: 06/12/2023]
Abstract
Heating rate has gained extensive attention in mechanistic understanding of physiological responses to changing thermal conditions in the context of climate change. In polymorphic gastropods, differences in the absorption of solar energy between dark- and light-coloured individuals lead to supposable differences in their heating rates and body temperatures in sunshine. In the present study, we examined the effect of heating rate on heart rate (HR) in a polymorphic gastropod Batillaria attramentaria. By using biomimetic models, we found that daily maximum temperature of snails with a dark unbanded shell (D-type morph) was higher than snails with a white line on the upper side of each whorl (UL-type morph) by 0.6 °C when exposed to sunlight, but there was no apparent difference in heating rates between D- and UL-type models. We measured HR of snails at various heating rates from 3.0 to 9.0 °C h-1. Faster heating rates significantly increased maximum thermal tolerance in both D- and UL-type snails, highlighting the importance to have thorough knowledge on the heating rate in the field to obtain accurate maximum thermal limit of gastropods. Critical temperature at which HR precipitously declines was higher in D-type snails than UL-type snails. Our results suggested that the impacts of heating rate as well as the shell colour should be considered to gain a mechanistic understanding of the population dynamics of polymorphic gastropods.
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Affiliation(s)
- Guodong Han
- College of Life Science, Yantai University, Shandong, 264005, China.
| | - Yinghui Du
- College of Life Science, Yantai University, Shandong, 264005, China
| | - Lina Du
- College of Life Science, Yantai University, Shandong, 264005, China
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10
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Knockdown of heat shock transcription factor 1 decreases temperature stress tolerance in Bemisia tabaci MED. Sci Rep 2022; 12:16059. [PMID: 36163391 PMCID: PMC9512819 DOI: 10.1038/s41598-022-19788-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 09/05/2022] [Indexed: 11/08/2022] Open
Abstract
The primary function of heat shock transcription factor (HSF) in the heat shock response is to activate the transcription of genes encoding heat shock proteins (HSPs). The phloem-feeding insect Bemisia tabaci (Gennadius) is an important pest of cotton, vegetables and ornamentals that transmits several plant viruses and causes enormous agricultural losses. In this study, the gene encoding HSF (Bthsf1) was characterized in MED B. tabaci. The full-length cDNA encoded a protein of 652 amino acids with an isoelectric point of 5.55. The BtHSF1 deduced amino acid sequence showed strong similarity to HSF in other insects. Expression analyses using quantitative real-time PCR indicated that Bthsf1 was significantly up-regulated in B. tabaci adults and pupae during thermal stress. Although Bthsf1 was induced by both hot and cold stress, the amplitude of expression was greater in the former. Bthsf1 had distinct, significant differences in expression pattern during different duration of high but not low temperature stress. Oral ingestion of dsBthsf1 repressed the expression of Bthsf1 and four heat shock proteins (Bthsp90, Bthsp70-3, Bthsp20 and Bthsp19.5) in MED B. tabaci during hot and cold stress. In conclusion, our results show that Bthsf1 is differentially expressed during high and low temperature stress and regulates the transcription of multiple hsps in MED B. tabaci.
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11
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Agyekum TP, Arko-Mensah J, Botwe PK, Hogarh JN, Issah I, Dwomoh D, Billah MK, Dadzie SK, Robins TG, Fobil JN. Effects of Elevated Temperatures on the Growth and Development of Adult Anopheles gambiae (s.l.) (Diptera: Culicidae) Mosquitoes. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1413-1420. [PMID: 35452118 PMCID: PMC9278826 DOI: 10.1093/jme/tjac046] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Indexed: 06/01/2023]
Abstract
Higher temperatures expected in a future warmer climate could adversely affect the growth and development of mosquitoes. This study investigated the effects of elevated temperatures on longevity, gonotrophic cycle length, biting rate, fecundity, and body size of Anopheles gambiae (s.l.) (Diptera: Culicidae) mosquitoes. Anopheles gambiae (s.l.) eggs obtained from laboratory established colonies were reared under eight temperature regimes (25, 28, 30, 32, 34, 36, 38, and 40°C), and 80 ± 10% RH. All adults were allowed to feed on a 10% sugar solution soaked in cotton wool; however, some mosquitoes were provided blood meal using guinea pig. Longevity was estimated for both blood-fed and non-blood-fed mosquitoes and analyzed using the Kaplan-Meier survival analysis. One-way ANOVA was used to test the effect of temperature on gonotrophic cycle length, biting rate, and fecundity. Adult measurement data were log-transformed and analyzed using ordinary least square regression with robust standard errors. Increasing temperature significantly decreased the longevity of both blood-fed (Log-rank test; X2(4) = 904.15, P < 0.001) and non-blood-fed (Log-rank test; X2(4) = 1163.60, P < 0.001) mosquitoes. In addition, the fecundity of mosquitoes decreased significantly (ANOVA; F(2,57) = 3.46, P = 0.038) with an increase in temperature. Body size (β = 0.14, 95% CI, 0.16, 0.12, P < 0.001) and proboscis length (β = 0.13, 95% CI, 0.17, 0.09, P < 0.001) significantly decreased with increasing temperature from 25 to 34°C. Increased temperatures expected in a future warmer climate could cause some unexpected effects on mosquitoes by directly influencing population dynamics and malaria transmission.
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Affiliation(s)
| | - John Arko-Mensah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Paul K Botwe
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Jonathan N Hogarh
- Department of Environmental Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ibrahim Issah
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Duah Dwomoh
- Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Maxwell K Billah
- Department of Animal Biology and Conservation Science, University of Ghana, Accra, Ghana
| | - Samuel K Dadzie
- Parasitology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Thomas G Robins
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Julius N Fobil
- Department of Biological, Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Accra, Ghana
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12
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Ngomane NC, Terblanche JS, Conlong DE. The Addition of Sterols and Cryoprotectants to Optimize a Diet Developed for Eldana saccharina Walker (Lepidoptera: Pyralidae) Using the Carcass Milling Technique. INSECTS 2022; 13:insects13040314. [PMID: 35447756 PMCID: PMC9029491 DOI: 10.3390/insects13040314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 02/01/2023]
Abstract
Various combinations and concentrations of cholesterol (C) and stigmasterol (S) were added into a base diet developed for Eldana saccharina. Survival of inoculated neonate was high on all diets (>92% at day 20 and >95% at day 27). Fastest larval development occurred on the minimum specification (MS) (+1.0 gS) and MS (+0.2 gC: 0.2 gS) diets (72 and 70% pupation respectively at day 20). Significantly slower development (15% pupation) occurred on the control diet at day 20. Female pupal weight increased when larvae fed on the MS (+0.1 gC), (+0.1 gS) and (+0.2 gC:0.2 gS) diets (0.2143 ± 0.00 g, 0.2271 ± 0.01 g and 0.2252 ± 0.01 g, respectively) as compared with the control diet (0.1886 ± 0.00 g). Adult emergence was significantly higher (100%) from the MS (+0.1 gS) and MS (+0.2 gC:0.2 gS) diets, as compared with the remaining sterol (95%) and control diets (97%). To potentially increase E. saccharina’s cold tolerance, inclusion of cryoprotectants L-proline (P) and trehalose (T) into the MS diet was investigated. Males from the MS (0.2 gP:0.2 gT), MS (0.5 gP:0.5 gT) and MS (1.0 gT) diets recovered fastest from chill coma treatment (204 ± 44 s, 215 ± 7 s and 215 ± 9 s, respectively) than those from the remaining cryoprotectant diets (305 ± 22 s). The addition of cryoprotectants severely reduced female fertility (<44%) when mated with non-chill coma exposed males. In contrast, eggs from females not exposed to chilling treatment were 84% fertile when mated with males from the same source. The MS (0.2 gC:0.2 gS) diet is the preferred choice to replace the currently used diet, reducing the larval growth period by 60% without negative effects on key life cycle parameters of E. saccharina.
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Affiliation(s)
- Nomalizo C. Ngomane
- Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch 7600, Western Cape, South Africa; (N.C.N.); (J.S.T.)
- South African Sugarcane Research Institute, 170 Flanders Drive, Mount Edgecombe 4300, KwaZulu-Natal, South Africa
| | - John S. Terblanche
- Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch 7600, Western Cape, South Africa; (N.C.N.); (J.S.T.)
| | - Des E. Conlong
- Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch 7600, Western Cape, South Africa; (N.C.N.); (J.S.T.)
- South African Sugarcane Research Institute, 170 Flanders Drive, Mount Edgecombe 4300, KwaZulu-Natal, South Africa
- Correspondence:
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13
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Huisamen EJ, Karsten M, Terblanche JS. Consequences of Thermal Variation during Development and Transport on Flight and Low-Temperature Performance in False Codling Moth (Thaumatotibia leucotreta): Fine-Tuning Protocols for Improved Field Performance in a Sterile Insect Programme. INSECTS 2022; 13:insects13040315. [PMID: 35447757 PMCID: PMC9030207 DOI: 10.3390/insects13040315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 02/01/2023]
Abstract
Here we aimed to assess whether variation in (1) developmental temperature and (2) transport conditions influenced the low-temperature performance and flight ability of false codling moth (FCM) adults in an SIT programme. To achieve the first aim, larvae were exposed to either a (control) (constant 25 °C), a cold treatment (constant 15 °C) or a fluctuating thermal regime (FTR) (25 °C for 12 h to 15 °C for 12 h) for 5 days, whereafter larvae were returned to 25 °C to pupate and emerge. After adult emergence, critical thermal minimum, chill coma recovery time, life history traits and laboratory flight ability were scored. For the second aim, adult FCM were exposed to 4 or 25 °C with or without vibrations to simulate road transportation. After the pre-treatments, flight ability, spontaneous behaviour (i.e., muscle coordination by monitoring whether the moth moved out of a defined circle or not) and chill coma recovery time were determined. The first experiment showed that FTR led to enhanced cold tolerance, increased flight performance and high egg-laying capacity with minimal costs. The second experiment showed that transport conditions currently in use did not appear to adversely affect flight and low-temperature performance of FCM. These results are important for refining conditions prior to and during release for maximum field efficacy in an SIT programme for FCM.
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Pak D, Carran S, Biddinger D, Nelson B, Bjørnstad ON. Incorporating diapause to predict the interannual dynamics of an important agricultural pest. POPUL ECOL 2022. [DOI: 10.1002/1438-390x.12117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Damie Pak
- Department of Biology Pennsylvania State University University Park Pennsylvania USA
| | - Spencer Carran
- Department of Ecology and Evolution University of Chicago Chicago Illinois USA
| | - David Biddinger
- Department of Entomology Pennsylvania State University Fruit Research & Extension Center Biglerville Pennsylvania USA
| | - Bill Nelson
- Department of Biology Queens University Kingston Ontario Canada
| | - Ottar N. Bjørnstad
- Department of Biology Pennsylvania State University University Park Pennsylvania USA
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15
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Zhang YJ, Jiang L, Ahamd S, Chen Y, Zhang JY, Stanley D, Miao H, Ge LQ. The octopamine receptor, OA2B2, modulates stress resistance and reproduction in Nilaparvata lugens Stål (Hemiptera: Delphacidae). INSECT MOLECULAR BIOLOGY 2022; 31:33-48. [PMID: 34480382 DOI: 10.1111/imb.12736] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 08/19/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
The brown planthopper (BPH), Nilaparvata lugens (Stål) is a resurgent pest of rice crops throughout Asia. We recently discovered that octopamine (OA) and OA2B2 operate in the BPH mating system, where it mediates a wide range of molecular, physiological and behavioural changes. Here, we report on outcomes of experiments designed to test the hypothesis that OA/OA2B2 signalling mediates responses to three abiotic stressors, starvation, high temperature (37 °C), and induced oxidative stress. We found per os RNAi-mediated OA2B2 silencing led to significantly decreased survival, measured in days, following exposure to each of these stressors. We selected a biologically costly process, reproductive biology, as a biotic stressor. Silencing of OA2B2 led to decreased total protein content in ovaries and fat bodies, downregulated expression of vitellogenin (Vg) and Vg receptor (VgR), inhibited fat body Vg protein synthesis, shortened the oviposition period, prolonged the preoviposition period, reduced the number of laid eggs, body weight and female longevity. In addition, the silencing treatments also led to inhibited ovarian development, and ovarian Vg uptake, reduced numbers of egg masses and offspring and lower hatching rates and population growth index. These data support our hypothesis that OA2B2 acts in mediating BPH resistance to biotic and abiotic stressors.
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Affiliation(s)
- Y J Zhang
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province, China
- College of Mechanical Engineering, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - L Jiang
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - S Ahamd
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - Y Chen
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - J Y Zhang
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - D Stanley
- USDA/Agricultural Research Service, Biological Control of Insects Research Laboratory, Columbia, MO, USA
| | - H Miao
- College of Mechanical Engineering, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - L Q Ge
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province, China
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16
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Bai J, Wang YC, Liu YC, Chang YW, Liu XN, Gong WR, Du YZ. Isolation of two new genes encoding heat shock protein 70 in Bemisia tabaci and analysis during thermal stress. Int J Biol Macromol 2021; 193:933-940. [PMID: 34728307 DOI: 10.1016/j.ijbiomac.2021.10.186] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 01/18/2023]
Abstract
The heat shock protein 70 family (HSP70) is among the most varied HSP family with respect to structure and function. The phloem-feeding insect Bemisia tabaci (Gennadius) is an important pest of cotton, vegetables and ornamentals that transmits several plant viruses and causes enormous agricultural losses. In this study, two new HSP70 genes (Bthsp70-2 and Bthsp70-3) were isolated from the MED cryptic species B. tabaci, an important phloem-feeding pest of vegetables and ornamentals. Bthsp70-2 and Bthsp70-3 encoded proteins comprised of 652 and 676 amino acids, and the deduced proteins were closely related to other HSP70s in Hemiptera. Expression analyses using real-time quantitative PCR indicated that Bthsp70-2 and Bthsp70-3 were induced in B. tabaci pupae and adults during high and low thermal stress. Bthsp70-2 and Bthsp70-3 exhibited similar, but not identical, expression patterns when exposed to different durations of high temperature stress. Oral ingestion of dsBthsp70 reduced the expression level of Bthsp70-2 and Bthsp70-3 in B. tabaci and increased the mortality of B. tabaci during heat shock. In conclusion, Bthsp70-2 and Bthsp70-3 exhibit different expression patterns during thermal stress, thus expanding the roles of HSPs in B. tabaci.
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Affiliation(s)
- Jing Bai
- College of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou 225009, China
| | - Yu-Cheng Wang
- College of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou 225009, China
| | - Yun-Cai Liu
- College of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou 225009, China
| | - Ya-Wen Chang
- College of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou 225009, China
| | - Xiao-Na Liu
- College of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou 225009, China
| | - Wei-Rong Gong
- Plant Protection and Quarantine Station of Jiangsu Province, Nanjing 21003, China
| | - Yu-Zhou Du
- College of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education, Yangzhou University, Yangzhou, China.
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Abstract
AbstractThe frequency, intensity, and duration of periods of extreme environmental warming are expected to rise over the next hundred years and play an increasing role in species loss resulting from climate change, and yet we know little about their potential future effects on variability in the composition of communities. This study analyzed patterns of species loss in a community of four rotifers and six ciliates exposed to different rates of extreme warming. Temperature of loss was positively correlated with warming rates for all species, consistent with theoretical frameworks suggesting that lower rates of warming increase exposure time and cumulative thermal stress at each temperature. The sequence of species loss during extreme warming depended on the environmental warming rate (i.e., warming rates had the capacity to drive reversals in the relative thermal tolerances of species), and changes in the sequence of species loss driven by the warming rate resulted in substantial variability in community composition. The results suggest that differences in warming rates across space and time may increase variability in community composition in ecosystems increasingly disturbed by extreme temperature, potentially altering interspecific interactions, the abiotic environment, and ecosystem function. Several ecological mechanisms may be responsible, singly or together, for changes in the sequence of species loss at different rates of warming, including (a) differences among species in their sensitivity to the intensity and duration of heat exposure, (b) the effects of warming rates on temperature-dependent interspecific interactions, and (c) differences in opportunities for evolution among species and across warming rates.
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18
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Nguyen HQ, Kim Y, Jang Y. De Novo Transcriptome Analysis Reveals Potential Thermal Adaptation Mechanisms in the Cicada Hyalessa fuscata. Animals (Basel) 2021; 11:ani11102785. [PMID: 34679807 PMCID: PMC8532856 DOI: 10.3390/ani11102785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/17/2021] [Accepted: 09/20/2021] [Indexed: 11/24/2022] Open
Abstract
Simple Summary In metropolitan Seoul and its vicinity, cicadas of the species Hyalessa fuscata living in warmer areas could tolerate the heat better than those living in cooler areas, but genetic mechanisms involved in better heat tolerance remained unclear. In this study, we examined differences in gene expression of cicadas living in a warm urban area, a cool urban area and a suburban area in three experimental treatments: no heating, 10 min heating and heating until the cicadas lost their mobility. Cicadas from the warm urban area changed their gene expressions the most. Activated genes were mostly related to heat shock, energy metabolism, and detoxification. These results suggested that under heat stress, cicadas inhabiting warm areas could differentially express genes to increase their thermal tolerance. Abstract In metropolitan Seoul, populations of the cicada Hyalessa fuscata in hotter urban heat islands (“high UHIs”) exhibit higher thermal tolerance than those in cooler UHIs (“low UHIs”). We hypothesized that heat stress may activate the expression of genes that facilitate greater thermal tolerance in high-UHI cicadas than in those from cooler areas. Differences in the transcriptomes of adult female cicadas from high-UHI, low-UHI, and suburban areas were analyzed at the unheated level, after acute heat stress, and after heat torpor. No noticeable differences in unheated gene expression patterns were observed. After 10 min of acute heat stress, however, low-UHI and suburban cicadas expressed more heat shock protein genes than high-UHI counterparts. More specifically, remarkable changes in the gene expression of cicadas across areas were observed after heat torpor stimulus, as represented by a large number of up- and downregulated genes in the heat torpor groups compared with the 10 min acute heat stress and control groups. High-UHI cicadas expressed the most differentially expressed genes, followed by the low-UHI and suburban cicadas. There was a notable increase in the expression of heat shock, metabolism, and detoxification genes; meanwhile, immune-related, signal transduction, and protein turnover genes were downregulated in high-UHI cicadas versus the other cicada groups. These results suggested that under heat stress, cicadas inhabiting high-UHIs could rapidly express genes related to heat shock, energy metabolism, and detoxification to protect cells from stress-induced damage and to increase their thermal tolerance toward heat stress. The downregulation of apoptosis mechanisms in high-UHI cicadas suggested that there was less cellular damage, which likely contributed to their high tolerance of heat stress.
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Affiliation(s)
- Hoa Quynh Nguyen
- Interdisciplinary Program of EcoCreative, Ewha Womans University, Ewhayeodaegil-52, Seoul 03760, Korea; (H.Q.N.); (Y.K.)
- Department of Life Sciences and Division of Ecoscience, Ewha Womans University, Ewhayeodaegil-52, Seoul 03760, Korea
- Institute of Chemistry, Vietnam Academy of Science and Technology, No. 18 Hoang Quoc Viet Street, Cau Giay District, Hanoi 10072, Vietnam
| | - Yuseob Kim
- Interdisciplinary Program of EcoCreative, Ewha Womans University, Ewhayeodaegil-52, Seoul 03760, Korea; (H.Q.N.); (Y.K.)
- Department of Life Sciences and Division of Ecoscience, Ewha Womans University, Ewhayeodaegil-52, Seoul 03760, Korea
| | - Yikweon Jang
- Interdisciplinary Program of EcoCreative, Ewha Womans University, Ewhayeodaegil-52, Seoul 03760, Korea; (H.Q.N.); (Y.K.)
- Department of Life Sciences and Division of Ecoscience, Ewha Womans University, Ewhayeodaegil-52, Seoul 03760, Korea
- Correspondence:
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19
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Gotcha N, Machekano H, Cuthbert RN, Nyamukondiwa C. Heat tolerance may determine activity time in coprophagic beetle species (Coleoptera: Scarabaeidae). INSECT SCIENCE 2021; 28:1076-1086. [PMID: 32567803 DOI: 10.1111/1744-7917.12844] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 06/10/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
Although reports have documented loss of species diversity and ecological services caused by stressful temperature changes that result from climate change, some species cope through behavioral compensation. As temperatures and magnitudes of temperature extremes increase, animals should compensate to maintain fitness (such as through temporary behavioral shifts in activity times). Appropriate timing of activity helps avoid competition across species. Although coprophagic dung beetles exhibit species-specific temporal activity times, it is unknown whether temperature drives evolution of these species-specific temporal activity times. Using nine dung beetle species (three each of diurnal, crepuscular, and nocturnal species), we explored differences in heat stress tolerance measured as critical thermal maxima (CTmax ; the highest temperature allowing activity) and heat knockdown time (HKDT; survival time under acute heat stress) across these species, and examined the results using a phylogenetically informed approach. Our results showed that day-active species had significantly higher CTmax (diurnal > crepuscular = nocturnal species), whereas crepuscular species had higher HKDT (crepuscular > nocturnal > diurnal species). There was no correlation between heat tolerance and body size across species with distinct temporal activity, and no significant phylogenetic constraint for activity. Species with higher CTmax did not necessarily have higher HKDT, which indicates that species may respond differently to diverse heat tolerance metrics. Acute heat tolerance for diurnal beetles indicates that this trait may constrain activity time and, under high acute temperatures with climate change, species may shift activity times in more benign environments. These results contribute to elucidate the evolution of foraging behavior and management of coprophagic beetle ecosystem services under changing environments.
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Affiliation(s)
- Nonofo Gotcha
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
| | - Honest Machekano
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
| | - Ross N Cuthbert
- GEOMAR, Helmholtz-Zentrum für Ozeanforschung Kiel, Kiel, Germany
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
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Engell Dahl J, Marti SL, Colinet H, Wiegand C, Holmstrup M, Renault D. Thermal plasticity and sensitivity to insecticides in populations of an invasive beetle: Cyfluthrin increases vulnerability to extreme temperature. CHEMOSPHERE 2021; 274:129905. [PMID: 33979910 DOI: 10.1016/j.chemosphere.2021.129905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/29/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Climate change increases average temperatures and the occurrence of extreme weather events, in turn accentuating the risk of organism exposure to temperature stress. When thermal conditions become stressful, the sensitivity of insects toward insecticides can be exacerbated. Likewise, exposure of insects to insecticides can subsequently influence their ability to handle stressful temperatures. Here, we investigated the effects of constant temperature and daily heat spikes, in presence/absence of insecticide treatment (cyfluthrin), on the condition (impairment of mobility) and thermal tolerance to cold (-6 °C) and heat (42.5 °C) of the terrestrial beetle Alphitobius diaperinus. The responses of insects from four populations (three farm-collected populations, one laboratory population) to different durations of extreme temperature exposure were compared. The results showed that the laboratory population was generally more sensitive to extreme cold and heat temperatures, with less than 50% of adults recovering after an exposure at -6 or +42.5 °C for 3h. Significant differences in the level of thermal tolerance were also found among insects from poultry farms. Cyfluthrin exposure incurred detrimental effects to insects' condition in all but one population. For two out of the four populations, mobility impairment was increased when adults were exposed to daily heat spikes (6 h per day at 38 °C) and cyfluthrin simultaneously, compared to cyfluthrin exposure at constant temperatures; yet, no significant interaction between the two stressors was found. Finally, using one farm collected population, effects of pre-exposure to cyfluthrin on extreme temperature tolerance provided another example of the toxicant-induced climate sensitivity in insects.
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Affiliation(s)
- Julie Engell Dahl
- University of Rennes, CNRS, ECOBIO [(Ecosystèmes, Biodiversité, évolution)], UMR 6553, F-35000, Rennes, France.
| | - Sapho-Lou Marti
- University of Rennes, CNRS, ECOBIO [(Ecosystèmes, Biodiversité, évolution)], UMR 6553, F-35000, Rennes, France
| | - Hervé Colinet
- University of Rennes, CNRS, ECOBIO [(Ecosystèmes, Biodiversité, évolution)], UMR 6553, F-35000, Rennes, France
| | - Claudia Wiegand
- University of Rennes, CNRS, ECOBIO [(Ecosystèmes, Biodiversité, évolution)], UMR 6553, F-35000, Rennes, France
| | - Martin Holmstrup
- University of Aarhus, Department of Bioscience, Section for Terrestrial Ecology, Vejlsøvej 25, 8600, Silkeborg, Denmark
| | - David Renault
- University of Rennes, CNRS, ECOBIO [(Ecosystèmes, Biodiversité, évolution)], UMR 6553, F-35000, Rennes, France; Institut Universitaire de France, 1 Rue Descartes, Paris, France
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21
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Rodgers EM, Gomez Isaza DF. Harnessing the potential of cross-protection stressor interactions for conservation: a review. CONSERVATION PHYSIOLOGY 2021; 9:coab037. [PMID: 35692493 PMCID: PMC8193115 DOI: 10.1093/conphys/coab037] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/15/2021] [Accepted: 05/09/2021] [Indexed: 05/07/2023]
Abstract
Conservation becomes increasingly complex as climate change exacerbates the multitude of stressors that organisms face. To meet this challenge, multiple stressor research is rapidly expanding, and the majority of this work has highlighted the deleterious effects of stressor interactions. However, there is a growing body of research documenting cross-protection between stressors, whereby exposure to a priming stressor heightens resilience to a second stressor of a different nature. Understanding cross-protection interactions is key to avoiding unrealistic 'blanket' conservation approaches, which aim to eliminate all forms of stress. But, a lack of synthesis of cross-protection interactions presents a barrier to integrating these protective benefits into conservation actions. To remedy this, we performed a review of cross-protection interactions among biotic and abiotic stressors within a conservation framework. A total of 66 publications were identified, spanning a diverse array of stressor combinations and taxonomic groups. We found that cross-protection occurs in response to naturally co-occurring stressors, as well as novel, anthropogenic stressors, suggesting that cross-protection may act as a 'pre-adaptation' to a changing world. Cross-protection interactions occurred in response to both biotic and abiotic stressors, but abiotic stressors have received far more investigation. Similarly, cross-protection interactions were present in a diverse array of taxa, but several taxonomic groups (e.g. mammals, birds and amphibians) were underrepresented. We conclude by providing an overview of how cross-protection interactions can be integrated into conservation and management actions and discuss how future research in this field may be directed to improve our understanding of how cross-protection may shield animals from global change.
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Affiliation(s)
- Essie M Rodgers
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Daniel F Gomez Isaza
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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22
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Liao ML, Li GY, Wang J, Marshall DJ, Hui TY, Ma SY, Zhang YM, Helmuth B, Dong YW. Physiological determinants of biogeography: The importance of metabolic depression to heat tolerance. GLOBAL CHANGE BIOLOGY 2021; 27:2561-2579. [PMID: 33666308 DOI: 10.1111/gcb.15578] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/25/2021] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
A quantitative understanding of physiological thermal responses is vital for forecasting species distributional shifts in response to climate change. Many studies have focused on metabolic rate as a global metric for analyzing the sublethal effects of changing environments on physiology. Thermal performance curves (TPCs) have been suggested as a viable analytical framework, but standard TPCs may not fully capture physiological responses, due in part to failure to consider the process of metabolic depression. We derived a model based on the nonlinear regression of biological temperature-dependent rate processes and built a heart rate data set for 26 species of intertidal molluscs distributed from 33°S to ~40°N. We then calculated physiological thermal performance limits with continuous heating using T 1 / 2 H , the temperature at which heart rate is decreased to 50% of the maximal rate, as a more realistic measure of upper thermal limits. Results indicate that heat-induced metabolic depression of cardiac performance is a common adaptive response that allows tolerance of harsh environments. Furthermore, our model accounted for the high inter-individual variability in the shape of cardiac TPCs. We then used these TPCs to calculate physiological thermal safety margins (pTSM), the difference between the maximal operative temperature (95th percentile of field temperatures) and T 1 / 2 H of each individual. Using pTSMs, we developed a physiological species distribution model (pSDM) to forecast future geographic distributions. pSDM results indicate that climate-induced species range shifts are potentially less severe than predicted by a simple correlative SDM. Species with metabolic depression below the optimum temperature will be more thermal resistant at their warm trailing edges. High intraspecific variability further suggests that models based on species-level vulnerability to environmental change may be problematic. This multi-scale, mechanistic understanding that incorporates metabolic depression and inter-individual variability in thermal response enables better predictions about the relationship between thermal stress and species distributions.
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Affiliation(s)
- Ming-Ling Liao
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, China
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Gao-Yang Li
- School of Environment, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Jie Wang
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, China
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - David J Marshall
- Environmental and Life Sciences, Faculty of Science, Universiti Brunei Darussalam, Gadong, Brunei Darussalam
| | - Tin Yan Hui
- Swire Institute of Marine Science, the University of Hong Kong, HKSAR, China
| | - Shu-Yang Ma
- Fisheries College, Ocean University of China, Qingdao, China
| | - Yi-Min Zhang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Brian Helmuth
- Marine Science Center, Northeastern University, Nahant, MA, USA
| | - Yun-Wei Dong
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, China
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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23
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Morgan Fleming J, Carter AW, Sheldon KS. Dung beetles show metabolic plasticity as pupae and smaller adult body size in response to increased temperature mean and variance. JOURNAL OF INSECT PHYSIOLOGY 2021; 131:104215. [PMID: 33662376 DOI: 10.1016/j.jinsphys.2021.104215] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 12/17/2020] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
Though organisms may use thermal plasticity to cope with novel temperature regimes, our understanding of plastic responses is limited. Research on thermal plasticity has traditionally focused on the response of organisms to shifts in mean temperatures. However, increased temperature variation can have a greater impact on organismal performance than mean temperature alone. In addition, thermal plasticity studies are often designed to investigate plasticity in response to more extreme temperatures despite the fact that organisms make physiological adjustments to diurnal temperature fluctuations that they experience. Using pupae of the dung beetle Onthophagus taurus, we investigated the potential for plasticity in response to increasing temperature mean and variance using thermal regimes that were well within the species critical thermal limits. We reared 40 beetles from egg to pupae (n = 20) or adults (n = 20) at one of nine incubation treatments, including all combinations of three mean temperatures (22, 24, 26 °C) and three amplitudes of fluctuation (±2, ±4, ±8 °C). To measure thermal plasticity of pupae, we quantified CO2 production across a range of temperatures (i.e., 15, 20, 25, and 30 °C) for 20 beetles per treatment. The relationship between CO2 production and temperature provides an estimate of energetic costs at a given temperature (i.e., using the intercept) and thermal sensitivity (i.e., using the slope). We reared the remaining O. taurus in each treatment (n = 20) to adulthood and then recorded mass (g) to determine body size, a proxy for fitness. Pupae exhibited thermal plasticity in response to the additive and interactive effects of temperature mean and variance. Pupae reared in the warmest and most variable treatment (26 ± 8 °C) showed the greatest decrease in overall metabolism compared to all other treatments, and adult beetles from this treatment (26 ± 8 °C) were also significantly smaller than adult beetles from any other treatment. We found that both temperature mean and variance contributed to thermal plasticity of pupae and had consequences for adult body size, a trait related to dung beetle fitness. Importantly, the temperatures we used in our treatments are not extreme and are likely well below the critical thermal maxima of the species, demonstrating that organisms can make adjustments to temperatures they experience across diurnal or seasonal timescales.
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Affiliation(s)
- J Morgan Fleming
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States.
| | - Amanda W Carter
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States.
| | - Kimberly S Sheldon
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States.
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Saeidi F, Mikani A, Moharramipour S. Thermal tolerance variations and physiological adjustments in a winter active and a summer active aphid species. J Therm Biol 2021; 98:102950. [PMID: 34016367 DOI: 10.1016/j.jtherbio.2021.102950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 03/24/2021] [Accepted: 03/31/2021] [Indexed: 01/02/2023]
Abstract
The Russian wheat aphid Diuraphis noxia (Kurdjumov) and melon aphid Aphis gossypii Glover are known as winter and summer active species, respectively. It is hypothesized that differences in the aphids' seasonal activities might be related to their response to temperature extremes and different physiological mechanisms. To study the aphids' thermal tolerance variations and mode of their physiological basis, they were cold acclimated at 20, 15, 10, 5, and 0 °C for 168 h (7 days) and heat acclimated at 20, 25, 30 °C for 168 h and 35 °C for 48 h. At the end of each thermal regime, survival at low and high temperatures was determined, and changes in sugars and polyols and heat shock protein 70 (Hsp70) were investigated. D. noxia was more cold-tolerant, while A. gossypii was a more heat-tolerant insect. The type and pattern of sugars and polyols were similar in both species under cold acclimation (ACC) and heat acclimation (HCC). In both species, glucose and mannitol were the major identified compounds involved in cold and heat tolerance. However, they showed different patterns of Hsp70 level, with D. noxia having a higher level of Hsp70 under ACC and A. gossypii having a higher level of Hsp70 under HCC. These results demonstrated that their differences in thermal tolerance might explain the seasonal activities of the aphids.
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Affiliation(s)
- Fatemeh Saeidi
- Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box: 14115-336, Tehran, Iran.
| | - Azam Mikani
- Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box: 14115-336, Tehran, Iran.
| | - Saeid Moharramipour
- Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box: 14115-336, Tehran, Iran.
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Hayakawa Y. N-acetyltyrosine-induced redox signaling in hormesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118990. [PMID: 33617888 DOI: 10.1016/j.bbamcr.2021.118990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 11/28/2022]
Abstract
A suite of adaptations allows insects to survive in hostile terrestrial environments for long periods of time. Temperature represents a key environmental factor for most ectothermic insects, and they rapidly acclimate to high and low temperatures. Vast amounts of data in this research field support the idea that an insect's ability to tolerate fluctuating temperatures can be regarded as a biphasic hormetic dose response. Observation indicates that their thermal hormetic response represents a conservative estimate of their intrinsic capacity for rapid adaptation to environmental changes in nature because they naturally experience diel or seasonal temperature fluctuations. It is therefore reasonable to suppose that the hormetic response in insects reflects a surplus physiological capacity to deal with temperature changes that they would experience naturally. Although it has been unknown how thermal acclimation is induced, a stress-dependent increase in N-acetyltyrosine (NAT) was recently found to occur in insect larvae who had endured high temperatures. NAT treatment was demonstrated to induce thermotolerance in several tested insect species. NAT was also identified in the serum of humans as well as mice, and its concentration in mice was shown to be increased by heat and restraint stress, with NAT pretreatment lowering the concentrations of corticosterone and peroxidized lipids in stressed mice. These recent findings may give us some hints about how long a hormetic response lasts. Here, I will discuss recent findings underlying hormetic responses induced by an intrinsic factor, NAT, and how the hormetic response may begin and end.
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Affiliation(s)
- Yoichi Hayakawa
- Department of Applied Biological Sciences, Saga University, Saga 840-8502, Japan.
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Esch ED, Horner RM, Krompetz DC, Moses-Gonzales N, Tesche MR, Suckling DM. Operational Parameters for the Aerial Release of Sterile Codling Moths Using an Uncrewed Aircraft System. INSECTS 2021; 12:159. [PMID: 33668567 PMCID: PMC7918654 DOI: 10.3390/insects12020159] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/06/2021] [Accepted: 02/10/2021] [Indexed: 02/06/2023]
Abstract
The codling moth is a serious pest of apples in most regions of the world where this fruit is produced. The sterile insect technique is one strategy used to control this pest and is employed as part of an area-wide integrated pest management program for the codling moth in British Columbia, Canada. Modified fixed wing aircraft are the most common method for the release of sterile insects in large area-wide pest management programs. However, aerial release with a full-size aircraft can be prohibitively expensive. We evaluated the use of small, uncrewed aircraft systems (UASs) for the release of sterile codling moths. Sterile codling moths released from greater altitudes were more broadly distributed and drifted more in strong winds, compared to those released from lower altitudes. Most of the released insects were recaptured in a 50 m wide swath under the release route. Recapture rates for aerially released insects were 40-70% higher compared to those released from the ground. UASs provide a promising alternative to ground release and conventional aircraft for the release of sterile codling moths.
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Affiliation(s)
- Evan D. Esch
- Okanagan-Kootenay Sterile Insect Release Board, Kelowna, BC VIW 3Z4, Canada;
- School of Engineering, University of British Columbia, Okanagan Campus, Kelowna, BC V1V 1V7, Canada
| | - Rachael M. Horner
- The New Zealand Institute for Plant and Food Research Limited, 8140 Christchurch, New Zealand; (R.M.H.); (D.M.S.)
| | | | | | - Melissa R. Tesche
- Okanagan-Kootenay Sterile Insect Release Board, Kelowna, BC VIW 3Z4, Canada;
| | - David Maxwell Suckling
- The New Zealand Institute for Plant and Food Research Limited, 8140 Christchurch, New Zealand; (R.M.H.); (D.M.S.)
- School of Biological Sciences, University of Auckland, 1072 Auckland, New Zealand
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Díaz-Ricaurte JC, Serrano FC. Short-term captivity does not affect immediate voluntary thermal maximum of a neotropical pitviper: Implications for behavioral thermoregulation. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 335:199-206. [PMID: 33258560 DOI: 10.1002/jez.2433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/15/2020] [Accepted: 11/18/2020] [Indexed: 11/07/2022]
Abstract
Ectotherms depend on temperature to maintain their physiological functions and through behavioral changes, they can avoid overheating in their habitats. The voluntary thermal maximum (VTMax ) represents the maximum temperature tolerated by individuals before actively moving to a colder place. However, if and how VTMax might change after capture and in captivity remains understudied. We investigate if measurements taken in captivity are a good proxy for thermal tolerance of wild individuals. As thermal history has been shown to affect behavioral response and physiological parameters, herein we hypothesized that VTMax of the neotropical viper Bothrops pauloensis varies throughout the captivity period. We measured the VTMax of individuals immediately after capture and in three trials during a short-term period in captivity. Measurements were done by recording their body temperature at which they exited a heating box experimental setup. In contrast to our hypothesis, the VTMax was not significantly affected by time in captivity but there was interindividual variation. There were also no significant differences between field and captivity measurements, in spite of the small effect size. Our results indicate that the VTMax of this snake population is not affected by a short-term captivity period. Furthermore, an invariant VTMax might indicate low phenotypic plasticity, as individuals do not appear to adjust their tolerance to short-term exposure to higher temperatures and potential vulnerability to threats such as global warming. We expect that our results can contribute to understanding the effect of captivity on thermal tolerance in neotropical squamates, allowing for insights into their thermal physiology and ecology.
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Affiliation(s)
- Juan C Díaz-Ricaurte
- Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
- Escola Superior de Agricultura Luiz de Queiroz, Programa de Pós-Graduação em Ecologia Aplicada, Universidade de São Paulo, Piracicaba, Brazil
- Semillero de Investigación en Ecofisiología y Biogeografía de Vertebrados, Grupo de investigación en Biodiversidad y Desarrollo Amazónico (BYDA), Centro de investigaciones Amazónicas Macagual-César Augusto Estrada González, Universidad de la Amazonia, Florencia, Caquetá, Colombia
| | - Filipe C Serrano
- Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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Pimsler ML, Oyen KJ, Herndon JD, Jackson JM, Strange JP, Dillon ME, Lozier JD. Biogeographic parallels in thermal tolerance and gene expression variation under temperature stress in a widespread bumble bee. Sci Rep 2020; 10:17063. [PMID: 33051510 PMCID: PMC7553916 DOI: 10.1038/s41598-020-73391-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 09/17/2020] [Indexed: 12/19/2022] Open
Abstract
Global temperature changes have emphasized the need to understand how species adapt to thermal stress across their ranges. Genetic mechanisms may contribute to variation in thermal tolerance, providing evidence for how organisms adapt to local environments. We determine physiological thermal limits and characterize genome-wide transcriptional changes at these limits in bumble bees using laboratory-reared Bombus vosnesenskii workers. We analyze bees reared from latitudinal (35.7-45.7°N) and altitudinal (7-2154 m) extremes of the species' range to correlate thermal tolerance and gene expression among populations from different climates. We find that critical thermal minima (CTMIN) exhibit strong associations with local minimums at the location of queen origin, while critical thermal maximum (CTMAX) was invariant among populations. Concordant patterns are apparent in gene expression data, with regional differentiation following cold exposure, and expression shifts invariant among populations under high temperatures. Furthermore, we identify several modules of co-expressed genes that tightly correlate with critical thermal limits and temperature at the region of origin. Our results reveal that local adaptation in thermal limits and gene expression may facilitate cold tolerance across a species range, whereas high temperature responses are likely constrained, both of which may have implications for climate change responses of bumble bees.
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Affiliation(s)
- Meaghan L Pimsler
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, 35487, USA.
| | - Kennan J Oyen
- Department of Zoology and Physiology and Program in Ecology, University of Wyoming, Laramie, WY, 82071, USA
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - James D Herndon
- USDA-ARS Pollinating Insects Research Unit, Utah State University, Logan, UT, 84322, USA
| | - Jason M Jackson
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, 35487, USA
| | - James P Strange
- USDA-ARS Pollinating Insects Research Unit, Utah State University, Logan, UT, 84322, USA
- Department of Entomology, The Ohio State University, Columbus, OH, 44691, USA
| | - Michael E Dillon
- Department of Zoology and Physiology and Program in Ecology, University of Wyoming, Laramie, WY, 82071, USA
| | - Jeffrey D Lozier
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, 35487, USA.
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Tarusikirwa VL, Mutamiswa R, English S, Chidawanyika F, Nyamukondiwa C. Thermal plasticity in the invasive south American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). J Therm Biol 2020; 90:102598. [PMID: 32479393 DOI: 10.1016/j.jtherbio.2020.102598] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 04/10/2020] [Accepted: 04/13/2020] [Indexed: 10/24/2022]
Abstract
South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating invasive global insect pest of tomato, Solanum lycopersicum (Solanaceae). In nature, pests face multiple overlapping environmental stressors, which may significantly influence survival. To cope with rapidly changing environments, insects often employ a suite of mechanisms at both acute and chronic time-scales, thereby improving fitness at sub-optimal thermal environments. For T. absoluta, physiological responses to transient thermal variability remain under explored. Moreso, environmental effects and physiological responses may differ across insect life stages and this can have implications for population dynamics. Against this background, we investigated short and long term plastic responses to temperature of T. absoluta larvae (4th instar) and adults (24-48 h old) from field populations. We measured traits of temperature tolerance vis critical thermal limits [critical thermal minima (CTmin) and maxima (CTmax)], heat knockdown time (HKDT), chill coma recovery time (CCRT) and supercooling points (SCP). Our results showed that at the larval stage, Rapid Cold Hardening (RCH) significantly improved CTmin and HKDT but impaired SCP and CCRT. Heat hardening in larvae impaired CTmin, CCRT, SCP, CTmax but not HKDT. In adults, both heat and cold hardening generally impaired CTmin and CTmax, but had no effects on HKDT, SCP and CCRT. Low temperature acclimation significantly improved CTmin and HKDT while marginally compromising CCRT and CTmax, whereas high temperature acclimation had no significant effects on any traits except for HKDT in larvae. Similarly, low and high temperature acclimation had no effects on CTmin, SCPs and CTmax, while high temperature acclimation significantly compromised adult CCRT. Our results show that larvae are more thermally plastic than adults and can shift their thermal tolerance in short and long timescales. The larval plasticity reported here could be advantageous in new envirnments, suggesting an asymmetrical ecological role of larva relative to adults in facilitating T. absoluta invasion.
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Affiliation(s)
- Vimbai L Tarusikirwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P. Bag 16, Palapye, Botswana
| | - Reyard Mutamiswa
- Department of Zoology and Entomology, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - Sinead English
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Frank Chidawanyika
- Department of Zoology and Entomology, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P. Bag 16, Palapye, Botswana.
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Berry R, López-Martínez G. A dose of experimental hormesis: When mild stress protects and improves animal performance. Comp Biochem Physiol A Mol Integr Physiol 2020; 242:110658. [PMID: 31954863 PMCID: PMC7066548 DOI: 10.1016/j.cbpa.2020.110658] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/13/2020] [Accepted: 01/13/2020] [Indexed: 01/22/2023]
Abstract
The adaptive response characterized by a biphasic curve is known as hormesis. In a hormesis framework, exposure to low doses leads to protective and beneficial responses while exposures to high doses are damaging and detrimental. Comparative physiologists have studied hormesis for over a century, but our understanding of hormesis is fragmented due to rifts in consensus and taxonomic-specific terminology. Hormesis has been and is currently known by multiple names; preconditioning, conditioning, pretreatment, cross tolerance, adaptive homeostasis, and rapid stress hardening (mostly low temperature: rapid cold hardening). These are the most common names used to describe adaptive stress responses in animals. These responses are mechanistically similar, while having stress-specific responses, but they all can fall under the umbrella of hormesis. Here we review how hormesis studies have revealed animal performance benefits in response to changes in oxygen, temperature, ionizing radiation, heavy metals, pesticides, dehydration, gravity, and crowding. And how almost universally, hormetic responses are characterized by increases in performance that include either increases in reproduction, longevity, or both. And while the field can benefit from additional mechanistic work, we know that many of these responses are rooted in increases of antioxidants and oxidative stress protective mechanisms; including heat shock proteins. There is a clear, yet not fully elucidated, overlap between hormesis and the preparation for oxidative stress theory; which predicts part of the responses associated with hormesis. We discuss this, and the need for additional work into animal hormetic effects particularly focusing on the cost of hormesis.
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Affiliation(s)
- Raymond Berry
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, United States of America
| | - Giancarlo López-Martínez
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58102, United States of America.
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Engell Dahl J, Bertrand M, Pierre A, Curtit B, Pillard C, Tasiemski A, Convey P, Renault D. Thermal tolerance patterns of a carabid beetle sampled along invasion and altitudinal gradients at a sub-Antarctic island. J Therm Biol 2019; 86:102447. [DOI: 10.1016/j.jtherbio.2019.102447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/09/2019] [Accepted: 10/28/2019] [Indexed: 01/08/2023]
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Manríquez PH, González CP, Brokordt K, Pereira L, Torres R, Lattuca ME, Fernández DA, Peck MA, Cucco A, Antognarelli F, Marras S, Domenici P. Ocean warming and acidification pose synergistic limits to the thermal niche of an economically important echinoderm. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 693:133469. [PMID: 31635008 DOI: 10.1016/j.scitotenv.2019.07.275] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/30/2019] [Accepted: 07/17/2019] [Indexed: 06/10/2023]
Abstract
To make robust projectios of the impacts of climate change, it is critical to understand how abiotic factors may interact to constrain the distribution and productivity of marine flora and fauna. We evaluated the effects of projected end of the century ocean acidification (OA) and warming (OW) on the thermal tolerance of an important living marine resource, the sea urchin Loxechinus albus, a benthic shallow water coastal herbivore inhabiting part of the Pacific coast of South America. After exposing young juveniles for a 1-month period to contrasting pCO2 (~500 and 1400 μatm) and temperature (~15 °C and 20 °C) levels, critical thermal maximum (CTmax) and minimum (CTmin) as well as thermal tolerance polygons were assessed based on self-righting success as an end point. Transcription of heat shock protein 70 (HSP70), a chaperone protecting cellular proteins from environmental stress, was also measured. Exposure to elevated pCO2 significantly reduced thermal tolerance by increasing CTmin at both experimental temperatures and decreasing CTmax at 20 °C. There was also a strong synergistic effect of OA × OW on HSP70 transcription levels which were 75 times higher than in control conditions. If this species is unable to adapt to elevated pCO2 in the future, the reduction in thermal tolerance and HSP response suggests that near-future warming and OA will disrupt their performance and reduce their distribution with ecological and economic consequences. Given the wider latitudinal range (6 to 56°S) and environmental tolerance of L. albus compared to other members of this region's benthic invertebrate community, OW and OA may cause substantial changes to the coastal fauna along this geographical range.
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Affiliation(s)
- Patricio H Manríquez
- Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile; Laboratorio de Ecología y Conducta de la Ontogenia Temprana (LECOT), Coquimbo, Chile.
| | - Claudio P González
- Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile; Laboratorio de Ecología y Conducta de la Ontogenia Temprana (LECOT), Coquimbo, Chile
| | - Katherina Brokordt
- Laboratorio de Fisiología y Genética Marina (FIGEMA), Universidad Católica del Norte, Coquimbo, Chile; Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile
| | - Luis Pereira
- Departamento de Acuicultura, Facultad de Ciencias de Mar, Universidad Católica del Norte, Coquimbo, Chile
| | - Rodrigo Torres
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Coyhaique, Chile; Centro de Investigación: Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Punta Arenas, Chile
| | - María E Lattuca
- Laboratorio de Ecología, Fisiología y Evolución de Organismos Acuáticos (LEFyE), Centro Austral de Investigaciones Científicas (CADIC-CONICET), Ushuaia, Argentina
| | - Daniel A Fernández
- Laboratorio de Ecología, Fisiología y Evolución de Organismos Acuáticos (LEFyE), Centro Austral de Investigaciones Científicas (CADIC-CONICET), Ushuaia, Argentina; Universidad Nacional de Tierra del Fuego, Instituto de Ciencias Polares, Ambiente y Recursos Naturales, Fuegia Basket 251, 9410 Ushuaia, Tierra del Fuego, Argentina
| | - Myron A Peck
- Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability, University of Hamburg, GroßeElbstrasse 133, D-22767 Hamburg, Germany
| | - Andrea Cucco
- CNR-IAMC-Istituto per l'Ambiente Marino Costiero, Localita Sa Mardini, Torregrande, Oristano 09170, Italy
| | - Fabio Antognarelli
- CNR-IAMC-Istituto per l'Ambiente Marino Costiero, Localita Sa Mardini, Torregrande, Oristano 09170, Italy
| | - Stefano Marras
- CNR-IAMC-Istituto per l'Ambiente Marino Costiero, Localita Sa Mardini, Torregrande, Oristano 09170, Italy
| | - Paolo Domenici
- CNR-IAMC-Istituto per l'Ambiente Marino Costiero, Localita Sa Mardini, Torregrande, Oristano 09170, Italy
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Ali S, Li P, Ali A, Hou M. Comparison of upper sublethal and lethal temperatures in three species of rice planthoppers. Sci Rep 2019; 9:16191. [PMID: 31700122 PMCID: PMC6838088 DOI: 10.1038/s41598-019-52034-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/12/2019] [Indexed: 11/09/2022] Open
Abstract
Temperature is an important environmental factor for ectotherms' fitness and survival. The upper sublethal and lethal temperatures were compared between adults of three closely related destructive planthopper species, the small brown planthopper (Laodelphax striatellus, SBPH), the brown planthopper (Nilaparvata lugens, BPH), and the white-backed planthopper (Sogatella furcifera, WBPH) in the absence and presence of the host plant (Oryza sativa, var. Taichong1). Values of the critical thermal maxima (CTmax) were higher in SBPH than in both BPH and WBPH and higher in BPH than in WBPH, and values of the heat coma temperatures (HCT) were higher in both BPH and SBPH than in WBPH. CTmax and HCT values were higher in the presence than in the absence of plant material. Between sexes, females generally showed higher CTmax and HCT than males. The upper lethal temperatures (ULT50) measured in the absence of plant material were not significantly different among the planthopper species. The planthoppers also exhibited different behaviors in an increasing temperature regime, with fewer insects dropping-off from the plant in SBPH than in BPH and WBPH. These results indicate that SBPH and BPH are more heat tolerant than WBPH. The findings highlight the biological divergence in closely related planthopper species and the importance of performing the heat tolerance measurement in an ecologically relevant setting, which serves to predict seasonal and spatial occurrence patterns of the destructive planthopper species.
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Affiliation(s)
- Shahbaz Ali
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Pei Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Asad Ali
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Maolin Hou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China. .,Scientific Observing and Experimental Station of Crop Pests in Guilin, Ministry of Agriculture, Guilin, 541399, China. .,Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, Changsha, 410128, China.
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Rusch TW, Adutwumwaah A, Beebe LE, Tomberlin JK, Tarone AM. The upper thermal tolerance of the secondary screwworm, Cochliomyia macellaria Fabricius (Diptera: Calliphoridae). J Therm Biol 2019; 85:102405. [DOI: 10.1016/j.jtherbio.2019.102405] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 08/14/2019] [Accepted: 08/25/2019] [Indexed: 12/01/2022]
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Motswagole R, Gotcha N, Nyamukondiwa C. Thermal Biology and Seasonal Population Abundance of Bactrocera dorsalis Hendel (Diptera: Tephritidae): Implications on Pest Management. INTERNATIONAL JOURNAL OF INSECT SCIENCE 2019; 11:1179543319863417. [PMID: 31488955 PMCID: PMC6710710 DOI: 10.1177/1179543319863417] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 06/24/2019] [Indexed: 06/10/2023]
Abstract
Since the first detection of Bactrocera dorsalis in Botswana in 2010, the establishment, spread, and response to prevailing Botswana microclimates under rapidly changing environments remain unknown. This study investigated the presence, seasonal population abundance, and thermal biology of B. dorsalis in Botswana. We measured B. dorsalis thermal tolerance vis critical thermal limits (CTLs) and lethal temperature assays (LTAs) to understand how temperature largely impacts on fitness and hence invasive potential. Seasonal monitoring results indicated B. dorsalis establishment in the Chobe district (its first area of detection). Trap catches showed continuous adult flies' presence all year round and high average monthly trap catches as compared with other districts. Furthermore, B. dorsalis was detected south of Botswana, including Kgatleng, Kweneng, South-east, and Southern districts. Critical thermal maxima (CTmax) to activity for adults and larvae were 46.16°C and 45.23°C, whereas critical thermal minima (CTmin) to activity for adults and larvae were 9.1°C and 7.3°C, respectively. Moreover, we found an improved CTmin for larvae at a slower ramping rate, indicating potential rapid cold hardening. The lower lethal temperature (LLT) and upper lethal temperature (ULT) assays revealed a reduction in survival at all the developmental stages as severity and duration of both temperature extremes increased. Microclimatic temperatures recorded in Botswana showed that environmental temperatures fall within the thermal breath of B. dorsalis activity measured here, indicating a potential conducive climate niche for the insect pest across the country, albeit other factors, e.g., host availability, play a significant role. These results therefore suggest that Botswana microclimatic temperatures aided B. dorsalis activity and invasion pathway are thus significant in mapping invasions and pest risk analysis, and may also aid in designing pest management strategies.
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Affiliation(s)
| | | | - Casper Nyamukondiwa
- Casper Nyamukondiwa, Department of Biological Sciences & Biotechnology, Botswana International University of Science & Technology, Private Bag 16, Palapye, Botswana.
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Multigenerational heat acclimation increases thermal tolerance and expression levels of Hsp70 and Hsp90 in the rice leaf folder larvae. J Therm Biol 2019; 81:103-109. [PMID: 30975406 DOI: 10.1016/j.jtherbio.2019.02.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/27/2019] [Accepted: 02/27/2019] [Indexed: 11/20/2022]
Abstract
Physiological response and acclimation to thermal stress is a key strategy of insects to cope with changing climate. The underlying mechanism of heat acclimation in insects is still unclear. Here, the heat selection and transcript level response in the larvae of the rice leaf folder Cnaphalocrocis medinalis Güenée, a serious pest of rice in summer, were studied. The survival and fecundity of larvae during multigenerational heat selection at 39 °C were examined, and heat tolerance and mRNA expression of heat shock protein 70 (Hsp70) and 90 (Hsp90) were examined under heat stress. The results showed that survival and fecundity of larvae increased notably and then kept constant after two or three generations of heat selection. Heat selection improved thermal tolerance of larvae. The Hsp70 mRNA expression of the 3rd-instar larvae increased in all five generations of heat selection, but Hsp90 increased only in the first two generations. The response of Hsp70 to 39 °C heat treatment in the larvae kept at 27 °C was different from the larvae exposed to the conditioning heat treatments, but the response of Hsp 90 was similar. Moreover, the Hsp70 and Hsp90 mRNA expression levels were significantly higher in the heat-acclimated larvae than that in the unacclimated larvae at a comparable duration of exposure to 37 and 41 °C. Selection at a high temperature across multiple generations led larvae to heat acclimation, and Hsp70 and Hsp90 were involved in this acclimation process.
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Chang YW, Zhang XX, Chen JY, Lu MX, Gong WR, Du YZ. Characterization of three heat shock protein 70 genes from Liriomyza trifolii and expression during thermal stress and insect development. BULLETIN OF ENTOMOLOGICAL RESEARCH 2019; 109:150-159. [PMID: 29743123 DOI: 10.1017/s0007485318000354] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Heat shock proteins (HSPs) participate in diverse physiological processes in insects, and HSP70 is one of the most highly conserved proteins in the HSP family. In this study, full-length cDNAs of three HSP70 genes (Lthsc70, Lthsp701, and Lthsp702) were cloned and characterized from Liriomyza trifolii, an important invasive pest of vegetable crops and horticultural crops worldwide. These three HSP70s exhibited signature sequences and motifs that are typical of the HSP70 family. The expression patterns of the three Lthsp70s during temperature stress and in different insect development stages were studied by real-time quantitative PCR. Lthsp701 was strongly induced by high- and low-temperature stress, but Lthsc70 and Lthsp702 were not very sensitive to temperature changes. All three Lthsp70s were expressed during insect development stages, but the expression patterns were quite different. The expression of Lthsc70 and Lthsp702 showed significant differences in expression during leafminer development; Lthsc70 was most highly expressed in female adults, whereas Lthsp702 was abundantly expressed in larvae and prepupae. Lthsp701 expression was not significantly different among leafminer stages. These results suggest that functional differentiation within the LtHSP70 subfamily has occurred in response to thermal stress and insect development.
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Affiliation(s)
- Y-W Chang
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University,Yangzhou 225009,China
| | - X-X Zhang
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University,Yangzhou 225009,China
| | - J-Y Chen
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University,Yangzhou 225009,China
| | - M-X Lu
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University,Yangzhou 225009,China
| | - W-R Gong
- Plant Protection and Quarantine Station of Jiangsu Province,Nanjing 21003,China
| | - Y-Z Du
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University,Yangzhou 225009,China
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Harada AE, Burton RS. Ecologically Relevant Temperature Ramping Rates Enhance the Protective Heat Shock Response in an Intertidal Ectotherm. Physiol Biochem Zool 2019; 92:152-162. [DOI: 10.1086/702339] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Moyen NE, Somero GN, Denny MW. Impact of heating rate on cardiac thermal tolerance in the California mussel, Mytilus californianus. J Exp Biol 2019; 222:jeb.203166. [DOI: 10.1242/jeb.203166] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 08/01/2019] [Indexed: 01/06/2023]
Abstract
Intertidal communities of wave-swept rocky shores have served as a powerful model system for experiments in ecology, and mussels (the dominant competitor for space in the mid-intertidal zone) play a central role in determining community structure in this physically stressful habitat. Consequently, our ability to account for mussels’ physiological responses to thermal stress affects ecologists’ abilities to predict the impacts of a warming climate on this ecosystem. Here, we examine the effect of heating rate on cardiac thermal tolerance in the ribbed mussel, Mytilus californianus, comparing populations from high and low sites in the intertidal zone where emersion duration leads to different mean daily heating rates. Two temperature-related cardiac variables were examined: 1) the critical temperature (Hcrit) at which heart rate (HR) precipitously declines, and 2) flatline temperature (FLT) where HR reaches zero. Mussels were heated in air at slow, moderate, and fast rates, and heart rate was measured via an infrared sensor affixed to the shell. Faster heating rates significantly increased Hcrit in high-, but not low-zone mussels, and Hcrit was higher in high vs. - mussels, especially at the fastest heating rate. By contrast, FLT did not differ between zones, and was minimally affected by heating rate. Since heating rate significantly impacted high- but not low-zone mussels’ cardiac thermal tolerance, realistic zone-specific heating rates must be used in laboratory tests if those tests are to provide accurate information for ecological models attempting to predict the effects of increasing temperature on intertidal communities.
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Affiliation(s)
- Nicole E. Moyen
- Hopkins Marine Station, Department of Biology, Stanford University, USA
| | - George N. Somero
- Hopkins Marine Station, Department of Biology, Stanford University, USA
| | - Mark W. Denny
- Hopkins Marine Station, Department of Biology, Stanford University, USA
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Cao JY, Xing K, Liu HP, Zhao F. Effects of developmental acclimation on fitness costs differ between two aphid species. J Therm Biol 2018; 78:58-64. [DOI: 10.1016/j.jtherbio.2018.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 08/31/2018] [Accepted: 09/08/2018] [Indexed: 01/24/2023]
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Manenti T, Cunha TR, Sørensen JG, Loeschcke V. How much starvation, desiccation and oxygen depletion can Drosophila melanogaster tolerate before its upper thermal limits are affected? JOURNAL OF INSECT PHYSIOLOGY 2018; 111:1-7. [PMID: 30273554 DOI: 10.1016/j.jinsphys.2018.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/27/2018] [Accepted: 09/27/2018] [Indexed: 06/08/2023]
Abstract
Heat tolerance is commonly assessed as the critical thermal maximum (CTmax) using the dynamic method exposing organisms to a gradually increasing (ramping) temperature until organisms fall into a coma. The CTmax estimate is dependent on the ramping rate, with decreased rates leading to longer treatments and ultimately lower CTmax estimates. There is a current discussion surrounding the physiological dynamics of the effect of the time of exposure by temperature interaction on these estimates. Besides temperature the time of exposure to limited food (starvation), desiccation, and reduced levels of oxygen or increased levels of CO2 may, in interaction with ramping rate, act as confounding factors when assessing upper thermal limits using the dynamic method. Here we test the role of the different potentially confounding factors for assaying thermal tolerance using a ramping assay under four different ramping rates, varying from 0.01 °C/min to 0.2 °C/min. We find that CTmax values are higher at faster ramping rates and that oxygen or CO2 concentration does not show any negative effect on the CTmax values obtained within the experimental pre-treatment period (32 h). Both water (up to 6 h) and food (up to 42 h) deprivation prior to assay showed a negative correlation with thermal tolerance of the flies. For both traits, we found a significant interaction with ramping rate, most likely due to prolonged assays at lower rates. However, as little water was lost during the ramping assay and as food deprivation only modestly affected CTmax values, results were very robust to the conditions experienced during the assay (even at slow rates) and mainly affected by the conditions experienced prior to performing the assay. Thus, for the most commonly applied experimental conditions CTmax estimates are unlikely to be biased or confounded by ramping rate, starvation, desiccation or deteriorating atmospheric composition.
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Affiliation(s)
- Tommaso Manenti
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114-116, Buildg. 1540, DK-8000 Aarhus C, Denmark
| | - Tomás Rocha Cunha
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114-116, Buildg. 1540, DK-8000 Aarhus C, Denmark
| | - Jesper Givskov Sørensen
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114-116, Buildg. 1540, DK-8000 Aarhus C, Denmark.
| | - Volker Loeschcke
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114-116, Buildg. 1540, DK-8000 Aarhus C, Denmark
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Mutamiswa R, Chidawanyika F, Nyamukondiwa C. Comparative assessment of the thermal tolerance of spotted stemborer, Chilo partellus (Lepidoptera: Crambidae) and its larval parasitoid, Cotesia sesamiae (Hymenoptera: Braconidae). INSECT SCIENCE 2018; 25:847-860. [PMID: 28374539 DOI: 10.1111/1744-7917.12466] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 03/09/2017] [Accepted: 03/19/2017] [Indexed: 06/07/2023]
Abstract
Under stressful thermal environments, insects adjust their behavior and physiology to maintain key life-history activities and improve survival. For interacting species, mutual or antagonistic, thermal stress may affect the participants in differing ways, which may then affect the outcome of the ecological relationship. In agroecosystems, this may be the fate of relationships between insect pests and their antagonistic parasitoids under acute and chronic thermal variability. Against this background, we investigated the thermal tolerance of different developmental stages of Chilo partellus Swinhoe (Lepidoptera: Crambidae) and its larval parasitoid, Cotesia sesamiae Cameron (Hymenoptera: Braconidae) using both dynamic and static protocols. When exposed for 2 h to a static temperature, lower lethal temperatures ranged from -9 to 6 °C, -14 to -2 °C, and -1 to 4 °C while upper lethal temperatures ranged from 37 to 48 °C, 41 to 49 °C, and 36 to 39 °C for C. partellus eggs, larvae, and C. sesamiae adults, respectively. Faster heating rates improved critical thermal maxima (CTmax ) in C. partellus larvae and adult C. partellus and C. sesamiae. Lower cooling rates improved critical thermal minima (CTmin ) in C. partellus and C. sesamiae adults while compromising CTmin in C. partellus larvae. The mean supercooling points (SCPs) for C. partellus larvae, pupae, and adults were -11.82 ± 1.78, -10.43 ± 1.73 and -15.75 ± 2.47, respectively. Heat knock-down time (HKDT) and chill-coma recovery time (CCRT) varied significantly between C. partellus larvae and adults. Larvae had higher HKDT than adults, while the latter recovered significantly faster following chill-coma. Current results suggest developmental stage differences in C. partellus thermal tolerance (with respect to lethal temperatures and critical thermal limits) and a compromised temperature tolerance of parasitoid C. sesamiae relative to its host, suggesting potential asynchrony between host-parasitoid population phenology and consequently biocontrol efficacy under global change. These results have broad implications to biological pest management insect-natural enemy interactions under rapidly changing thermal environments.
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Affiliation(s)
- Reyard Mutamiswa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Private Bag 16, Palapye, Botswana
| | - Frank Chidawanyika
- Agricultural Research Council, Plant Protection Research, Weeds Division, Private Bag X6006, Hilton 3245, South Africa
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Private Bag 16, Palapye, Botswana
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Machekano H, Mutamiswa R, Nyamukondiwa C. Evidence of rapid spread and establishment of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in semi-arid Botswana. ACTA ACUST UNITED AC 2018. [DOI: 10.1186/s40066-018-0201-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Cavieres G, Bogdanovich JM, Toledo P, Bozinovic F. Fluctuating thermal environments and time-dependent effects on fruit fly egg-hatching performance. Ecol Evol 2018; 8:7014-7021. [PMID: 30073063 PMCID: PMC6065328 DOI: 10.1002/ece3.4220] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 12/24/2022] Open
Abstract
Organismal performance in a changing environment is dependent on temporal patterns and duration of exposure to thermal variability. We experimentally assessed the time-dependent effects of thermal variability (i.e., patterns of thermal exposure) on the hatching performance of Drosophila melanogaster. Flies were collected in central Chile and maintained for four generations in laboratory conditions. Fourth generation eggs were acclimated to different thermal fluctuation cycles until hatching occurred. Our results show that the frequency of extreme thermal events has a significant effect on hatching success. Eggs exposed to 24 hr cycles of thermal fluctuation had a higher proportion of eggs that hatched than those acclimated to shorter (6 and 12 hr) and longer cycles (48 hr). Furthermore, eggs subjected to frequent thermal fluctuations hatched earlier than those acclimated to less frequent thermal fluctuations. Overall, we show that, egg-to-adult viability is dependent on the pattern of thermal fluctuations experienced during ontogeny; thus, the pattern of thermal fluctuation experienced by flies has a significant and until now unappreciated impact on fitness.
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Affiliation(s)
- Grisel Cavieres
- Departamento de EcologíaCenter of Applied Ecology and Sustainability (CAPES‐UC) Facultad de Ciencias BiológicasPontificia Universidad Católica de ChileSantiagoChile
- CCT‐Mendoza CONICETGrupo de Investigaciones de la BiodiversidadCONICETInstituto Argentino de Investigaciones de Zonas ÁridasMendozaArgentina
| | - José M. Bogdanovich
- Departamento de EcologíaCenter of Applied Ecology and Sustainability (CAPES‐UC) Facultad de Ciencias BiológicasPontificia Universidad Católica de ChileSantiagoChile
- Centro de Investigación e Innovación para el Cambio ClimáticoUniversidad Santo TomásSantiagoChile
| | - Paloma Toledo
- Departamento de EcologíaCenter of Applied Ecology and Sustainability (CAPES‐UC) Facultad de Ciencias BiológicasPontificia Universidad Católica de ChileSantiagoChile
| | - Francisco Bozinovic
- Departamento de EcologíaCenter of Applied Ecology and Sustainability (CAPES‐UC) Facultad de Ciencias BiológicasPontificia Universidad Católica de ChileSantiagoChile
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Kingsolver JG, Umbanhowar J. The analysis and interpretation of critical temperatures. ACTA ACUST UNITED AC 2018; 221:jeb.167858. [PMID: 29724777 DOI: 10.1242/jeb.167858] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 04/26/2018] [Indexed: 01/08/2023]
Abstract
Critical temperatures are widely used to quantify the upper and lower thermal limits of organisms. But measured critical temperatures often vary with methodological details, leading to spirited discussions about the potential consequences of stress and acclimation during the experiments. We review a model based on the simple assumption that failure rate increases with increasing temperature, independent of previous temperature exposure, water loss or metabolism during the experiment. The model predicts that mean critical thermal maximal temperature (CTmax) increases non-linearly with starting temperature and ramping rate, a pattern frequently observed in empirical studies. We then develop a statistical model that estimates a failure rate function (the relationship between failure rate and current temperature) using maximum likelihood; the best model accounts for 58% of the variation in CTmax in an exemplary dataset for tsetse flies. We then extend the model to incorporate potential effects of stress and acclimation on the failure rate function; the results show how stress accumulation at low ramping rate may increase the failure rate and reduce observed values of CTmax We also applied the model to an acclimation experiment with hornworm larvae that used a single starting temperature and ramping rate; the analyses show that increasing acclimation temperature significantly reduced the slope of the failure rate function, increasing the temperature at which failure occurred. The model directly applies to critical thermal minima, and can utilize data from both ramping and constant-temperature assays. Our model provides a new approach to analyzing and interpreting critical temperatures.
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Affiliation(s)
- Joel G Kingsolver
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - James Umbanhowar
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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Nyamukondiwa C, Chidawanyika F, Machekano H, Mutamiswa R, Sands B, Mgidiswa N, Wall R. Climate variability differentially impacts thermal fitness traits in three coprophagic beetle species. PLoS One 2018; 13:e0198610. [PMID: 29874290 PMCID: PMC5991409 DOI: 10.1371/journal.pone.0198610] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 05/22/2018] [Indexed: 01/10/2023] Open
Abstract
While the impacts of extreme and rising mean temperatures are well documented, increased thermal variability associated with climate change may also threaten ectotherm fitness and survival, but remains poorly explored. Using three wild collected coprophagic species Copris elphenor, Metacatharsius opacus and Scarabaeus zambezianus, we explored the effects of thermal amplitude around the mean on thermal tolerance. Using standardized protocols, we measured traits of high- (critical thermal maxima [CTmax] and heat knockdown time [HKDT]) and -low temperature tolerance (critical thermal minima [CTmin], chill coma recovery time [CCRT] and supercooling points [SCPs]) following variable temperature pulses (δ0, δ3, δ6 and δ9°C) around the mean (27°C). Our results show that increased temperature variability may offset basal and plastic responses to temperature and differs across species and metrics tested. Furthermore, we also show differential effects of body mass, body water content (BWC) and body lipid content (BLC) on traits of thermal tolerance. For example, body mass significantly influenced C. elphenor and S. zambezianus CTmax and S. zambezianus HKDT but not CTmin and CCRT. BWC significantly affected M. opacus and C. elphenor CTmax and in only M. opacus HKDT, CTmin and CCRT. Similarly, BLC only had a significant effect for M opacus CTmin. These results suggest differential and species dependent effects of climate variability of thermal fitness traits. It is therefore likely that the ecological services provided by these species may be constrained in the face of climate change. This implies that, to develop more realistic predictions for the effects of climate change on insect biodiversity and ecosystem function, thermal variability is a significant determinant.
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Affiliation(s)
- Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
- * E-mail:
| | - Frank Chidawanyika
- Agricultural Research Council, Plant Protection Research Institute, Weeds Division, Hilton, South Africa
- School of Lifesciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Honest Machekano
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - Reyard Mutamiswa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - Bryony Sands
- School of Biological Sciences, University of Bristol, United Kingdom
| | - Neludo Mgidiswa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - Richard Wall
- School of Biological Sciences, University of Bristol, United Kingdom
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Mutamiswa R, Chidawanyika F, Nyamukondiwa C. Thermal plasticity potentially mediates the interaction between host Chilo partellus Swinhoe (Lepidoptera: Crambidae) and endoparasitoid Cotesia flavipes Cameron (Hymenoptera: Braconidae) in rapidly changing environments. PEST MANAGEMENT SCIENCE 2018; 74:1335-1345. [PMID: 29193807 DOI: 10.1002/ps.4807] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Increasing climatic average temperatures and variability elicit various insect physiological responses that affect fitness and survival and may influence subsequent trophic interactions in agroecosystems. In this background, we investigated short- and long-term plastic responses to temperature of the laboratory-reared stemborer Chilo partellus and its larval endoparasitoid Cotesia flavipes. RESULTS Rapid cold- and heat-hardening effects in C. partellus larvae, pupae and adults and C. flavipes adults were highly significant (P < 0.001). High-temperature acclimation improved critical thermal limits and heat knockdown time in C. partellus larvae and C. flavipes adults, respectively. Low-temperature acclimation enhanced the supercooling point in C. flavipes and the chill coma recovery time in both C. partellus larvae and C. flavipes adults. CONCLUSION The results of this study suggest that thermal plasticity may enhance the survival of these two species when they are subjected to lethal low and high temperatures. However, C. partellus appeared to be more plastic than C. flavipes. These results have three major implications: (1) C. partellus may inhabit slightly warmer environments than C. flavipes, suggesting a potential mismatch in biogeography; (2) host-parasitoid relationships are complex and are probably trait dependent, and (3) host-parasitoid differential thermal plastic responses may offset biocontrol efficacy. These results may help inform biocontrol decision making under conditions of global change. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Reyard Mutamiswa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - Frank Chidawanyika
- Agricultural Research Council, Plant Protection Research, Weeds Division, Hilton, South Africa
- School of Lifesciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
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Mutamiswa R, Machekano H, Chidawanyika F, Nyamukondiwa C. Thermal resilience may shape population abundance of two sympatric congeneric Cotesia species (Hymenoptera: Braconidae). PLoS One 2018; 13:e0191840. [PMID: 29438408 PMCID: PMC5810992 DOI: 10.1371/journal.pone.0191840] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 01/11/2018] [Indexed: 11/24/2022] Open
Abstract
Basal and plasticity of thermal tolerance determine abundance, biogeographical patterns and activity of insects over spatial and temporal scales. For coexisting stemborer parasitoids, offering synergistic impact for biological control, mismatches in thermal tolerance may influence their ultimate impact in biocontrol programs under climate variability. Using laboratory-reared congeneric parasitoid species Cotesia sesamiae Cameron and Cotesia flavipes Cameron (Hymenoptera: Braconidae), we examined basal thermal tolerance to understand potential impact of climate variability on their survival and limits to activity. We measured upper- and lower -lethal temperatures (ULTs and LLTs), critical thermal limits [CTLs] (CTmin and CTmax), supercooling points (SCPs), chill-coma recovery time (CCRT) and heat knock-down time (HKDT) of adults. Results showed LLTs ranging -5 to 5°C and -15 to -1°C whilst ULTs ranged 35 to 42°C and 37 to 44°C for C. sesamiae and C. flavipes respectively. Cotesia flavipes had significantly higher heat tolerance (measured as CTmax), as well as cold tolerance (measured as CTmin) relative to C. sesamiae (P<0.0001). While SCPs did not vary significantly (P>0.05), C. flavipes recovered significantly faster following chill-coma and had higher HKDT compared to C. sesamiae. The results suggest marked differential basal thermal tolerance responses between the two congeners, with C. flavipes having an advantage at both temperature extremes. Thus, under predicted climate change, the two species may differ in phenologies and biogeography with consequences on their efficacy as biological control agents. These results may assist in predicting spatio-temporal activity patterns which can be used in integrated pest management programs under climate variability.
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Affiliation(s)
- Reyard Mutamiswa
- Department of Biology and Biotechnological Sciences, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - Honest Machekano
- Department of Biology and Biotechnological Sciences, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - Frank Chidawanyika
- Agricultural Research Council, Plant Protection Research, Weeds Division, Hilton, South Africa
- School of Lifesciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Casper Nyamukondiwa
- Department of Biology and Biotechnological Sciences, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
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Gotcha N, Terblanche JS, Nyamukondiwa C. Plasticity and cross-tolerance to heterogeneous environments: divergent stress responses co-evolved in an African fruit fly. J Evol Biol 2017; 31:98-110. [PMID: 29080375 DOI: 10.1111/jeb.13201] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/10/2017] [Accepted: 10/17/2017] [Indexed: 01/16/2023]
Abstract
Plastic adjustments of physiological tolerance to a particular stressor can result in fitness benefits for resistance that might manifest not only in that same environment but also be advantageous when faced with alternative environmental stressors, a phenomenon termed 'cross-tolerance'. The nature and magnitude of cross-tolerance responses can provide important insights into the underlying genetic architecture, potential constraints on or versatility of an organism's stress responses. In this study, we tested for cross-tolerance to a suite of abiotic factors that likely contribute to setting insect population dynamics and geographic range limits: heat, cold, desiccation and starvation resistance in adult Ceratitis rosa following acclimation to all these isolated individual conditions prior to stress assays. Traits of stress resistance scored included critical thermal (activity) limits, chill coma recovery time (CCRT), heat knockdown time (HKDT), desiccation and starvation resistance. In agreement with other studies, we found that acclimation to one stress typically increased resistance for that same stress experienced later in life. A more novel outcome, however, is that here we also found substantial evidence for cross-tolerance. For example, we found an improvement in heat tolerance (critical thermal maxima, CTmax ) following starvation or desiccation hardening and improved desiccation resistance following cold acclimation, indicating pronounced cross-tolerance to these environmental stressors for the traits examined. We also found that two different traits of the same stress resistance differed in their responsiveness to the same stress conditions (e.g. HKDT was less cross-resistant than CTmax ). The results of this study have two major implications that are of broader importance: (i) that these traits likely co-evolved to cope with diverse or simultaneous stressors, and (ii) that a set of common underlying physiological mechanisms might exist between apparently divergent stress responses in this species. This species may prove to be a valuable model for future work on the evolutionary and mechanistic basis of cross-tolerance.
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Affiliation(s)
- N Gotcha
- Department of Biological Sciences and Biotechnology Sciences, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - J S Terblanche
- Department of Conservation Ecology and Entomology, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
| | - C Nyamukondiwa
- Department of Biological Sciences and Biotechnology Sciences, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
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Alford L, Kishani Farahani H, Pierre JS, Burel F, van Baaren J. Why is there no impact of the host species on the cold tolerance of a generalist parasitoid? JOURNAL OF INSECT PHYSIOLOGY 2017; 103:71-77. [PMID: 29038015 DOI: 10.1016/j.jinsphys.2017.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 10/06/2017] [Accepted: 10/12/2017] [Indexed: 06/07/2023]
Abstract
For generalist parasitoids such as those belonging to the Genus Aphidius, the choice of host species can have profound implications for the emerging parasitoid. Host species is known to affect a variety of life history traits. However, the impact of the host on thermal tolerance has never been studied. Physiological thermal tolerance, enabling survival at unfavourable temperatures, is not a fixed trait and may be influenced by a number of external factors including characteristics of the stress, of the individual exposed to the stress, and of the biological and physical environment. As such, the choice of host species is likely to also have implications for the thermal tolerance of the emerging parasitoid. The current study aimed to investigate the effect of cereal aphid host species (Sitobion avenae, Rhopalosiphum padi and Metopolophium dirhodum) on adult thermal tolerance, in addition to sex and size, of the aphid parasitoids Aphidius avenae, Aphidius matricariae and Aphidius rhopalosiphi. Results revealed no effect of host species on the cold tolerance of the emerging parasitoid, as determined by CTmin and Chill Coma, for all parasitoid species. Host species significantly affected the size of the emerging parasitoid for A. rhopalosiphi only, with individuals emerging from R. padi being significantly larger than those emerging from S. avenae, although this did not correspond to a difference in thermal tolerance. Furthermore, a significant difference in the size of male and female parasitoids was observed for A. avenae and A. matricariae, although, once again this did not correspond to a difference in cold tolerance. It is suggested that potential behavioural thermoregulation via host manipulation may act to influence the thermal environment experienced by the wasp and thus wasp thermal tolerance and, in doing so, may negate physiological thermal tolerance or any impact of the aphid host.
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Affiliation(s)
- Lucy Alford
- UMR 6553 ECOBIO, Université de Rennes I, Avenue du Général Leclerc, 35042 Rennes Cedex, France; Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK.
| | | | - Jean-Sébastien Pierre
- UMR 6553 ECOBIO, Université de Rennes I, Avenue du Général Leclerc, 35042 Rennes Cedex, France
| | - Françoise Burel
- UMR 6553 ECOBIO, Université de Rennes I, Avenue du Général Leclerc, 35042 Rennes Cedex, France
| | - Joan van Baaren
- UMR 6553 ECOBIO, Université de Rennes I, Avenue du Général Leclerc, 35042 Rennes Cedex, France
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